Compensations for an Assistive Robotic Interface

Background: Homonymous visual field defects (VFD) are common following stroke, and often recover, partially or fully, by unknown mechanisms. In clinical practice, visual field recovered on perimetry is often considered perceptually normal. However, studies have shown contrast sensitivity (CS) deficits in patients with stroke and homonymous VFD. This study investigated the origin of visual CS loss in patients with VFD due to stroke. We hypothesised that CS deficits would be found in visual field areas appearing normal on perimetry, in patients with ischaemic stroke affecting the retrochiasmal visual system, and that the spatiotemporal properties of this CS loss would be consistent with those of ‘blindsight', perhaps suggesting similar underlying mechanisms. Methods: CS measurements were made in 20 healthy participants, and in 7 patients with stroke causing homonymous VFD sparing foveal vision, measured using Humphrey static perimetry (SITA-Fast 24-2 procedure). Importantly, patients with concomitant visuospatial neglect were excluded. CS measurements were made using a modification of the method of increasing contrast, corrected for reaction time. Three spatial stimuli were used, at several spatial frequencies: (1) large sinusoidal gratings; (2) foveal Gabor patches; and (3) Gabor patches presenting in the putatively recovered visual field, near VFD. Stimuli with different temporal profiles were used to selectively stimulate transient and sustained visual channels, to provide insight into mechanisms of visual loss and/or recovery. Analysis of variance (ANOVA) was used in the analysis of the measurements, allowing for correction for age and stimulus eccentricity. Results: ANOVA for sustained grating stimuli showed orientation-selective (horizontal) CS loss (p = 0.025); no such loss was apparent in the central visual field (foveal Gabor stimuli). Localised CS close to VFD was reduced in stroke-affected hemifields compared with unaffected hemifields (p ≤ 0.005), though these areas appeared normal on perimetry. In these areas, CS was relatively preserved for transient compared with sustained stimuli (Wilcoxon signed rank tests). Conclusions: The finding of specific CS deficits in the normal-appearing visual field of patients with homonymous VFD due to stroke suggests that static perimetry provides an inadequate assessment of visual function in these patients, with clear implications for testing of vision in clinical practice. The results are consistent with relative sparing of the transient/magnocellular visual channel. These findings demand further investigation. If confirmed in larger, longitudinal studies, this will have important implications for the mechanisms of recovery, and may provide a target for visual rehabilitation - for example, using repeated detection practice (‘perceptual learning').

Placing inspection time, reaction time, and perceptual speed in the broader context of cognitive ability: The VPR model in the Lothian Birth Cohort 1936

The Cattell‐Horn‐Carroll Theory of Cognitive Abilities

IntroductionThe relationship between visual abilities and punching performance has received considerable attention in sports science, but research on female amateur boxers remains limited. This study investigates the correlation between visual‑motor abilities and punching performance in female amateur boxers.MethodsA total of 26 trained female boxers participated in the study, and their visual abilities were assessed using the Senaptec Sensory Station. The visual ability tests included measures of visual clarity (VC), contrast sensitivity (CS), depth perception (DP), perceptual span (PS), multiple object tracking (MOT), reaction time (RT), eye‑hand coordination (EHC), and Go/No‑Go (GNG). Punching performance was analyzed by evaluating the hit percentage (%Hit) in the National Boxing Championship.ResultsPearson correlation analysis showed that punching accuracy (%Hit) was strongly correlated with EHC, RT, PS, and DP. Stepwise regression analysis confirmed that these visual abilities significantly predicted punching performance, with EHC, RT, PS, and DP explaining 93.1% of the variance in %Hit.DiscussionThe results highlight the significant role of visual motor abilities in enhancing the punching performance of female boxers. The study suggests that training programs targeting these visual abilities, especially EHC, RT, and DP, could improve boxing performance. This research provides valuable insights into the role of vision in female boxing and suggests future directions for visual training in combat sports.

This case-control study investigated whether defects in visual field contrast sensitivity are associated with exposure to occupational levels of pesticides in agricultural workers. Twenty-seven individuals exposed to occupational levels of pesticides (exposed group) from 14 agricultural systems and 27 non-exposed individuals (non-exposed group) were measured using standard automated perimetry (30-2 full threshold). Visual sector analysis, targeting regions of the optic nerve head, was performed to examine for potential region-specific sensitivity differences. Participants also underwent comprehensive assessments, including general optometric examinations and demographic surveys. Symptoms and signs of neurotoxicity were assessed using the modified Q16 neurotoxic symptom questionnaire and biological testing for abnormal levels of Substance P in tears (an inflammatory marker associated with chemical exposure) and cholinesterase (which is inhibited by pesticides) in blood samples. Signs of chemical exposure were found as indicated by significantly higher levels of neurotoxic symptoms, higher concentrations of Substance P and lower levels of cholinesterase in the exposed group. Visual field global indices showed differences in contrast sensitivity between the exposed and non-exposed groups, with the exposed group demonstrating significantly lower means and larger pattern-standard deviations. Notably, visual field sector analysis revealed comparatively lower contrast sensitivity at nasal locations surrounding the optic nerve head in the exposed group. This study found deficits in visual field contrast sensitivity to be associated with pesticide exposure, and selective loss at nasal locations centred on the optic nerve head may indicate retinal toxicity. These findings suggest the utility of visual field assessment as a potential method to evaluate pesticide-related health implications. The results highlight the need for ongoing monitoring and protective measures for agricultural workers exposed to pesticides to prevent potential visual and neurological damage.

PurposeVisual acuity (VA) and contrast sensitivity (CS) characterize different aspects of visual function. Whereas VA is a standard test in routine eye exams and clinical trials, CS is often not included. We investigated the pathology-specific dissociation between VA and CS by quantifying and comparing the relationship between these two measures in common ocular pathologies.MethodsVA and CS data were assembled from 1113 subjects, including groups with cataract (n = 450), age-related macular degeneration (AMD; n = 232), glaucoma (n = 100), retinitis pigmentosa (RP; n = 87), and normal ocular health (n = 244). VA and CS were measured by the Early Treatment Diabetic Retinopathy Study chart and Pelli–Robson chart, respectively.ResultsEven when VA was relatively normal (<0.3 logMAR), the four ocular pathology groups showed quantitatively different mean CS deficits relative to normal controls, ranging from –0.01 log units for cataract to 0.23 log units for RP. When the entire range of VA was considered, the corresponding deficits in CS were noticeably different across these four groups, being least for cataract and progressively more severe for glaucoma, AMD, and RP. For every 1.0 logMAR loss of VA, the corresponding deficit in CS ranged from 0.22 logCS for cataract to 0.97 logCS for RP.ConclusionsThe quantitative relationship between VA and CS depends on the ocular pathology. CS appears to provide valuable complementary information to VA in the early detection of eye disease and when evaluating visual impairment.

BackgroundPatients with retinal diseases frequently complain of poor visual function even when visual acuity is relatively unaffected. This clinical finding has been attributed to deficits in contrast sensitivity (CS). The purpose of our study was to evaluate the CS in patients with clinical and genetic diagnosis of inherited retinal degeneration (IRD) and relatively preserved visual acuity.MethodsSeventeen patients (30 eyes) with IRD and visual acuity of 20/40 or better, and 18 controls (18 eyes) without any ocular condition underwent slit lamp examination, visual acuity testing via standard Snellen chart testing, CS testing via the Quick Contrast Sensitivity Function (QCSF), and Spectral Domain Optical Coherence Tomography (SD-OCT). CS were measured at 1.0, 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree (cpd). T tests with general estimated equations were used to compare CS between groups. Wald chi square followed by pairwise comparisons was used to compare CS between multiple groups.ResultsWe included 12 patients with rod-cone dystrophy (RCD), 3 patients with Stargardt disease (STGD) and 2 patients with Best disease. Patients with IRD had significantly worse CS than controls (p < 0.001) in all spatial frequencies. Patients with STGD had more marked deficits in CS than patients with Best disease (p < 0.001) and RCD (p < 0.001) despite having similar visual acuities.ConclusionPatients with IRD, especially patients with STGD with relatively preserved visual acuity have marked deficits in CS when measured across a range of spatial frequencies. We recommend that clinical trials for STGD incorporate CS measured over a range of spatial frequencies as a secondary clinical endpoint for monitoring visual function. CS may provide an explanation for complaints of visual dysfunction when visual acuity is not significantly altered.

In responding to the construction quantification learning effect and academic achievements of the quantity surveying learners, the study examines the effects of several potential characteristics concerning specific individual differences such as cognitive abilities and demographics. Specifically, the study aims to compare the effects of individual differences in cognitive thinking, such as low or high spatial visualisation abilities and the demographics of learners (gender and age), towards the construction quantification achievement. The target respondent would be the quantity surveying learners (potential semi-professional graduates) in Malaysian public institutions. This preliminary study used a quantitative approach to determine the critical factors and indicators that lead to learners’ moderate performance in the construction quantification course. A significant relationship between spatial visualisation ability (SVA) and the construction quantification achievement concludes that spatial intelligence serves as a framework to support people facing difficulties interpreting 2-dimensional (2D) graphics representation. Seemingly, SVA is crucial to be possessed by the potential learners who wish to enrol in the quantity surveying programme. To successfully function and become more independent construction quantification learners in quantity surveying technical disciplines programme, these people need to have more spatial ability. However, there are no significant differences between different gender and age learners categories in spatial visualisation ability test (SVAT) scores and the construction quantification test (CQT) scores as the findings were insignificant. The result obtained in this study hoped to clarify the importance of cognitive ability and demographic differences to the construction quantification achievement.

Contrast sensitivity, optotype acuity and fixation eye movement abnormalities in amblyopia under binocular viewing

As we age, several cognitive abilities decline, yet the ability to regulate emotions remains stable (or improves) even when the emotion regulation strategy required is mentally effortful (i.e., requires cognitive resources for success). The primary aim of this dissertation was to examine how expressive suppression (i.e., the inhibition of emotional responses and behavior) impacts cognitive processing speed following a sadness induction procedure. Groups of younger (participants between 18 – 29 years of age) and older (participants over 60 years of age) adults completed three measures of processing speed, first following a no-regulation control condition. The control condition began with participants watching three film clips from BBC’s Planet Earth series. On a later day of testing, all participants completed the processing speed measures following an effortful emotion regulation experimental condition. The experimental condition began with participants watching three film clips meant to induce negative emotion, namely sadness. Prior to the experimental context of this study, all participants completed several individual difference measures of cognitive ability (e.g., crystallized intelligence, working memory, fluid reasoning, and rational thinking).It was predicted that younger adults would outperform older adults on processing speed tasks, and that effortful emotion regulation would generally impair subsequent cognitive ability (i.e., processing speed). Furthermore, it was predicted that younger adults would be impacted to a greater degree than older adults. Additionally, individual differences in cognitive ability were examined as potential moderators of the impact of effortful emotion regulation on processing speed. Main effects for both age group and emotion regulation, but no interaction effect, materialized in the project. First, younger adults outperformed older adults on the measures of processing speed, supporting the prediction made about this effect. However, regardless of age group, processing speed performance during expressive suppression was facilitated, not impaired. Additionally, these results persisted when statistically controlling for participants fluid reasoning and working memory abilities.This project supported previous findings regarding lifespan trends of cognitive development by demonstrating that, with age, processing speed performance and fluid reasoning ability declined, but crystallized intelligence ability increased. Following expressive suppression strategy use there was no cognitive impairment demonstrated regardless of age group. In fact, processing speed ability increased from the control to experimental test sessions implying that the degree of emotion regulation employed by participants led to facilitation. Additionally, the prediction that younger adults would require increased mental effort to use expressive suppression was not fully supported. However, the association did trend in the predicted direction. Furthermore, the requirement of increased mental effort during expressive suppression strategy use materialized for the entire sample of data and among older adult participants. These findings imply that effortful emotion regulation depletes cognitive resources regardless of the age of participants. In conclusion, self-regulation of negative emotions may function under a similar hyperbolic function like psychosocial stress. Additional lines of research with stronger methodological control are needed to determine these similarities. In conclusion, it is possible that small to moderate degrees of emotion regulation led to facilitation effects of concurrent cognitive ability due to increased focus and vigilance required during the regulation effort. However, larger degrees of regulation may lead to impairments expected by the predictions made in the study. This determination requires further testing under rigorous experimental control.

Sport visual ability plays an important role in the performance of elite athletes in competition. However, its relationship with boxers' performance has not been fully understood. This study investigated the relationship between sports visual abilities and in-competition punching performance in 26 highly trained male amateur boxers. Ten visual abilities of the boxers were tested using the Senaptec Sensory Station (Senaptec, Beaverton, OR, United States), including Visual Clarity (VC), Contrast Sensitivity (CS), Depth Perception (DP), Near Far Quickness (NFQ), Target Capture (TC), Perception Span (PS), Multiple Object Tracking (MOT), Eye-Hand Coordination (EHC), Go/No Go (GNG), and Reaction Time (RT). Performance analyses were conducted on national boxing championships conducted by the boxers to analyze their punching accuracy. Correlation and regression analyses showed that punch performance %Hit was very strong correlated with DP, EHC, GNG, and RT, and showed a strong correlation with VC, CS, and PS. %Hit was moderate correlated with MOT, while there was no correlation with NFQ and TC. In addition, RT, EHC, and DP are important visual ability variables for boxers. The results of this study indicate that there is an overall relationship between sports visual ability and boxing performance, but there is also a specific relationship between variables in visual ability and boxing performance, especially faster reaction times, better processing of visual information, and decision-making abilities, and the ability to accurately recognize the distance and position of an opponent and their punches are essential for enhancing boxing performance. Further studies are needed to investigate the relationship between sport visual ability and more comprehensive performance in boxers, and the possibility of enhancing performance through specific visual training.

Previous studies have shown that, in patients with lesions of the visual pathway, contrast sensitivity (CS) measured with stationary sine-wave gratings can demonstrate deficits, that is, anomalies in pattern detection. The purpose of this study was to investigate whether temporal processing can be affected in demyelinating lesions of the visual pathway. CS was measured for eight spatial frequencies (SF), using stationary and temporally modulated stimuli in a group of 10 patients with multiple sclerosis or optic neuritis. A control group was composed of 48 normal eyes. With stationary stimuli, CS losses were found in 17 eyes of patients; 11 of these eyes were 'unaffected'. The importance of the CS measurements in detecting early subclinical visual damage is emphasized. The effect of temporal modulation in patients with CS deficits was different from that observed in normals: CS deficits were modified by temporal variation in three distinct manners. In 7 eyes (type 1 effect), temporal modulation reduced the deficit at all SFs. In type 2 (5 eyes), the effect was reversed at low and high SFs: the deficit was reduced at low SFs (below 2-3 cycles/deg) and aggravated at high SFs. In type 3 (4 eyes), CS deficit was aggravated over most SFs. Thus these patients exhibited anomalies of the spatiotemporal responses which could not be predicted by the CS to stationary stimuli. Some theoretical models of spatiotemporal processing proposed in normal vision might account for our results. Possible explanations of these findings are proposed and discussed.

Visual contrast sensitivity in Alzheimer’s disease, mild cognitive impairment, and older adults with cognitive complaints

Background Contrast sensitivity (CS) of amblyopia has been extensively studied,but its relationship with spatial frequency channels needs further research. Objective The purpose of this study was to investigate the reasons of the CS deficits in amblyopia through comparing the differences in CS between amblyopic and normal eyes from the point of view of spatial frequency channels. Methods The CS values of 166 normal children eyes and 143 amblyopic children abnormal eyes were measured by adopting OPTEC 6500.Then,spatial frequency channels' tuning curves were derived via principal component analysis and non-orthogonal rotation.Also,numbers and bandwidths of channels were calculated using the method of full width at half maximum ( FWHM ).All of these were used to analyze the variations of CS between amblyopia and normal eyes by comparing the numbers and the bandwidths of the channels.The reliability of spatial frequency channel was verified by a cross-validation study of 43 amblyopic children. Result At spatial frequency of 1.5,3.0,6.0,12.0,18.0 cpd,the mean of CS of amblyopia were 36.35±21.40,50.33 ± 33.46,46.88 ± 41.72,16.24 ± 17.26,4.67 ± 5.79,and the mean of CS of normal eyes were 49.49±24.69,87.23±40.87,93.18±51.99.36.63±24.72,15.70±13.87,with the rank-sum test results were H =27.83,66.61,68.34,78.23,89.88,P＜0.05.There existed three spatial frequency channels in both amblyopia and normal eyes.At the peaks of 3.0,6.0 and 12.0 cpd,the bandwidths of normal eyes were 1.03,1.02 and 0.99 octaves,and the bandwidths of amblyopia were 1.04,1.01 and 0.73 octaves. Conclusions The reduction in bandwidths of the corresponding spatial frequency channels may cause the CS deficits in amblyopia. Key words: Contrast sensitivity; Spatial frequency channel; Variance analysis; Amblyopia

The Relationship between Hue Discrimination and Contrast Sensitivity Deficits in Patients with Diabetes Mellitus